The present invention relates to seat belt apparatuses fixed at vehicle seats restraining occupants with seat belts in emergency situations, such as a vehicle collision.
In general, a seat belt apparatus includes: a seat belt retractor fixed to a vehicle body at a portion in the vicinity of a vehicle seat, the seat belt retractor retracting a seat belt while allowing withdrawal or retraction of the seat belt in ordinary situations and restraining an occupant by inhibiting the withdrawal of the seat belt in emergency situations such as a vehicle collision; the seat belt extending from the seat belt retractor with a tip end thereof connected to a lap anchor section, which is, for instance, fixed to the vehicle body at a portion near the outer side of the vehicle seat, for restraining the occupant with the seat belt fastened; a buckle, for example, fixed to the vehicle body at a portion near the inner side of the vehicle seat; and a tongue provided at the seat belt so that the tongue can slide freely along the seat belt and can be engaged with and disengaged from the buckle. When the seat belt is extended across the shoulder, chest and waist of the occupant and the tongue is engaged with the buckle, the seat belt is fastened about the occupant.
With the seat belt fastened, the seat belt is relatively loosely retracted by a seat belt retractor and fits to the occupant while allowing the withdrawal or retraction of the seat belt such that the occupant does not feel too tightly restrained in ordinary situations. Meanwhile, when a large vehicle deceleration occurs in emergency situations, such as a vehicle collision, the force attempting to move the occupant forward due to the inertial force, the seat belt is inhibited from being withdrawn so as to restrain the occupant.
This conventional seat belt apparatus may be provided with a pretensioner for restraining the occupant immediately with a large restraining force according to enhancement on the restraining by eliminating looseness of the seat belt in emergency situations, such as a vehicle collision, and by restraining the seat belt immediately. If such a pretensioner is provided at the lap anchor section, the tip end of the seat belt is connected to the pretensioner through the lap anchor. A lap anchor cover is provided to cover the connection portion. In such a seat belt apparatus, the pretensioner operates to pull the seat belt connected to the lap anchor to eliminate the looseness of the seat belt in emergency situations as described above, thereby immediately restraining the seat belt.
The lap anchor cover guides the lap anchor and the seat belt in the retraction of the seat belt. For example, a configuration is disclosed in Japanese Unexamined Patent Application Publication No. 2004-322739 (which is incorporated by reference herein in its entirety) that a seat belt is sewn with sewing thread and bound to a lap anchor cover in the vicinity of an insertion hole. With this related art, when the seat belt is drawn in, the binding portion sewn with the sewing thread would be broken due to the draw-in force.